VARIABILITY IN DIFFERENT PHYSICAL AND BIOCHEMICAL CHARACTERISTICS OF 6 TOMATO GENOTYPES ACCORDING TO STAGES OF RIPENESS

A wide range of firmness, surface colour, percentage of locular tissue , vitamin C, citric acid, malic acid, oxalic acid, fructose, glucose, sucrose and acid invertase activity (soluble and cell wall-bound fract ion) was found in various cultivars of tomato. The fruit firmness and external chroma (C and hue angle (arctan b*/a*) changed significantly as the fruit passed through various stages of maturity. In all the ge notypes studied, reducing sugar content increased with advancing matur ity with concomitant increase in soluble acid invertase activity. Sucr ose was found highest in mature green stage and remained low throughou t the ripening. Citric acid was the primary organic acids followed by malic and oxalic acid. Organic acids and vitamin C increased with the maturity of fruit and their peak were found at pink stage, but decline d slightly al the red stage. The sugar/organic acid ratios was almost equal at the mature, green and pink stage, but then increased at final stage of ripening. This increase was primarily attributed to a substa ntial increase of monosaccharide along with a decrease in organic acid s. These patterns of physical and biochemical changes during maturatio n of fruit was nearly identical in all genotypes studied. Of the six g enotypes tested, Momotaro and TM0126 showed better performance to the most of the parameters studied, as compared to cv. Manik. Furthermore, cherry tomatoes had higher organic acids, higher soluble sugars, and higher percentage of locular tissue than that of the large-fruited typ es.